Mount the jackass ass

This is supposed to be some sort of animalistic thing, you think. You get down on your knees behind Jenny, and pull down your tights and hook them below your balls. Your cock is not yet fully hard, so you rouse it by holding it and dragging it back and forth across the outside of Jenny pussy lips. She is quite wet, and the wetness helps excite you, as you excite her, by rubbing across her clit. By the time your cock is fully erect, Jenny is bucking her hips back into your thrusts, trying to slip herself around your cock. You are careful to keep yourself on her outside, though, until your cock has reached its full length, a truly monstrous twelve inches.

You back away from Jenny, and place the wet tip of your cock against Jenny's asshole. Jenny probably picked you out of the crowd when she saw the size of your package through your tights, but even she is a little apprehensive, having felt your true length as you rubbed against her. No matter. This is how animals do it, you think. You lean forward, and put much of your weight on Jenny's back, then begin to thrust. You go as quickly as you can without overly hurting Jenny, but it still takes a while for you to get yourself into her, even with her help. Jenny moves her hips to try and coax you in, and to make room for you, but you are so big that even she is gasping at the effort.

By the time you thrust your way deep enough into Jenny's ass that you can feel your balls touch her legs, she is a panting, gasping mess. You pause for a moment, glad to have reached this small milestone, and something inspires you to let out a neighing noise, doing your best to imitate a horse. Jenny responds with her braying as best as she can through her gasping. You take this as a signal, and are off for the races. You grip her torso tightly in a bearhug, and start pumping your pelvis in and out of her, plunging in and out of Jenny's ass. Jenny's braying picks up in pace, her "Eee-anhh ee-anhh"s coming in time with your thrusting, and occasionally peppered with a somewhat more human moan, as you fuck her anally as quickly and as forcefully as you can.

You hear her make a gurgling noise, and hope that that means she's cumming, because you can feel your horse-cock explosively cum into her at that second. Your rhythmic thrusting degrades into a spasmodic jerking as her tight ass prolongs and strengthens your already copious and voluminous orgasmic discharge. One of your last jerking thrusts is powerful enough to knock Jenny off balance, and you both fall forward so that you are laying flat on your stomachs, with you on top of her, and your giant cock still embedded in her ass.